• Title, Summary, Keyword: infinite elements

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THREE-DIMENSIONAL INFINITE ELEMENTS FOR WAVE FORCE EVALUATION OF OFFSHORE STRUCTURES (해양구조물의 파력산정을 위한 3-차원 무한요소)

  • 박우선;윤정방
    • Computational Structural Engineering
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    • v.4 no.4
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    • pp.135-144
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    • 1991
  • The finite element technique incorporatating infinite elements is applied to analyzing the general three dimensional wave-structure interaction problems within the limits of linear wave theory. The hydrodynamic forces are assumed to be inertially dominated, and viscous effects are neglected. In order to analyze the corresponding boundary value problems efficiently, two types of elements are developed. One is the infinite element for modeling the radiation condition at infinity, and the other is the fictitious bottom boundary element for the case of deep water. To validate those elements, numerical analyses are performed for several floating structures. Comparisons with the results by using other available solution methods show that the present method incorporating the infinite and the fictitious bottom boundary elements gives good results.

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Direct Calculation of A Matrix of Single Machine Connected to Infinite Bus : Including Excitation System (발전기-무한모선계통의 A행열의 직접 계산법 : 여자계통을 고려한 경우)

  • Kwon, Sae-Hyuk;Kim, Dug-Young
    • Proceedings of the KIEE Conference
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    • pp.216-220
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    • 1989
  • Direct calculation algorithm for the elements of A matrix is suggested for a single machine connected to the infinite bus. Excitation system and power system stabilizer are included. When A matrix is partitioned into seven submatrices, we can identify the location of non-zero elements and formula for each element. No matrix inversion and multiplication are necessary.

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Combination of Element-Free Galerkin Method and Infinite Elements (무요소법과 무한요소의 결합에 관한 연구)

  • 이상호;김태연
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.76-83
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    • 2001
  • In this study, a new method coupling of Element-Free Galerkin(EFG) method and Infinite Elements(IE) method is presented for extending application of the EFG method to engineering problems in unbounded domain. EFG method and IE method are briefly reviewed, and then the coupling procedure of the two methods is proposed. Numerical Algorithm by way of EFG-lE coupling technique is also developed. Numerical results illustrate the performance of the proposed technique. The accuracy of numerical solutions by the developed algorithm is guaranteed in comparing those of the other methods.

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CLOSED IDEALS IN A SEMIFINITE, INFINITE VON NEUMANN ALGEBRA, ARISING FROM RELATIVE RANKS OF ITS ELEMENTS

  • Lee, Sa-Ge;Kim, Sang-Moon;Chi, Dong-Pyo
    • Bulletin of the Korean Mathematical Society
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    • v.21 no.2
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    • pp.107-113
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    • 1984
  • Throughout the paper let A be a semifinite, infinite von Neumann algebra acting on a Hilbert space H, .alpha. an infinite cardinal. The main purpose of our work is to give several characterizations of a class of closed ideals in A, by introducing the notions of relative ranks of elements in A and the relative .alpha.-topology on H. The relative .alphi.-topology is an analogue to the .alpha.-topology that we have defined in ([7], [8]). The present work is regarded as an extension of [7], [8] and motivated by works of M. Breuer ([1], [2]), V. Kaftal ([5], [6]) and M.G. Sonis [9].

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Infinite Elements for Soil-Structure Interaction Analysis (지반-구조물의 상호작용 해석을 위한 무한요소)

  • 양신추;윤정방;이인모
    • Computational Structural Engineering
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    • v.2 no.3
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    • pp.85-95
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    • 1989
  • This paper presents a study of soil-structure interaction problems using infinite elements. The infinite elements are formulated for homogeneous and layered soil media, based on approximate expressions for three components of propagating waves, namely the Rayleigh, compressive and shear waves. The integration scheme which was proposed for problems with single wave component by waves. The integration scheme which was proposed for problems with single wave component by Zenkiewicz is expanded to the multi-waves problem. Verifications are carried out on rigid circular footings which are placed on and embedded in elastic half space. Numerical analysis is performed for a containment structure of a nuclear power plant subjected to a horizontal seismic excitation.

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Nonlinear interaction analysis of infilled frame-foundation beam-homogeneous soil system

  • Hora, M.S.
    • Coupled systems mechanics
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    • v.3 no.3
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    • pp.267-289
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    • 2014
  • A proper physical modeling of infilled building frame-foundation beam-soil mass interaction system is needed to predict more realistic and accurate structural behavior under static vertical loading. This is achieved via finite element method considering the superstructure, foundation and soil mass as a single integral compatible structural unit. The physical modelling is achieved via use of finite element method, which requires the use of variety of isoparametric elements with different degrees of freedom. The unbounded domain of the soil mass has been discretized with coupled finite-infinite elements to achieve computational economy. The nonlinearity of soil mass plays an important role in the redistribution of forces in the superstructure. The nonlinear behaviour of the soil mass is modeled using hyperbolic model. The incremental-iterative nonlinear solution algorithm has been adopted for carrying out the nonlinear elastic interaction analysis of a two-bay two-storey infilled building frame. The frame and the infill have been considered to behave in linear elastic manner, whereas the subsoil in nonlinear elastic manner. In this paper, the computational methodology adopted for nonlinear soil-structure interaction analysis of infilled frame-foundation-soil system has been presented.

A study on the topographical and geotechnical effects in 2-D soil-structure interaction analysis under ground motion

  • Duzgun, Oguz Akin;Budak, Ahmet
    • Structural Engineering and Mechanics
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    • v.40 no.6
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    • pp.829-845
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    • 2011
  • This paper evaluates the effects of topographical and geotechnical irregularities on the dynamic response of the 2-D soil-structure systems under ground motion by coupling finite and infinite elements. A numerical procedure is employed, and a parametric study is carried out for single-faced slope topographies. It is concluded that topographic conditions may have important effects on the ground motion along the slope. The geotechnical properties of the soil will also have significantly amplified effects on the whole system motion, which cannot be neglected for design purposes. So, dynamic response of a soil-structure systems are primarily affected by surface shapes and geotechnical properties of the soil. Location of the structure is another parameter affecting the whole system response.

Infinite Element for the Scaled Boundary Analysis of Initial Valued on-Homogeneous Elastic Half Space (초기값을 갖는 비동질무한영역의 해석을 위한 비례경계무한요소법)

  • Lee, Gye-Hee;Deeks, Andrew J.
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.21 no.2
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    • pp.199-208
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    • 2008
  • In this paper, to analyze the initial valued non-homogeneous elastic half space by the scaled boundary analysis, the infinite element approach was introduced. The free surface of the initial valued non-homogeneous elastic half space was modeled as a circumferential direction of boundary scaled boundary coordinate. The infinite element was used to represent the infinite length of the free surface. The initial value of material property(elastic modulus) was considered by the combination of the position of the scaling center and the power function of the radial direction. By use of the mapping type infinite element, the consistent elements formulation could be available. The performance and the feasibility of proposed approach are examined by two numerical examples.

An Empirical Central Limit Theorem for the Kaplan-Meier Integral Process on [0,$\infty$)

  • Bae, Jong-Sig
    • Journal of the Korean Statistical Society
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    • v.26 no.2
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    • pp.231-243
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    • 1997
  • In this paper we investigate weak convergence of the intergral processes whose index set is the non-compact infinite time interval. Our first goal is to develop the empirical central limit theorem as random elements of [0, .infty.) for an integral process which is constructed from iid variables. In developing the weak convergence as random elements of D[0, .infty.), we will use a result of Ossiander(4) whose proof heavily depends on the total boundedness of the index set. Our next goal is to establish the empirical central limit theorem for the Kaplan-Meier integral process as random elements of D[0, .infty.). In achieving the the goal, we will use the above iid result, a representation of State(6) on the Kaplan-Meier integral, and a lemma on the uniform order of convergence. The first result, in some sense, generalizes the result of empirical central limit therem of Pollard(5) where the process is regarded as random elements of D[-.infty., .infty.] and the sample paths of limiting Gaussian process may jump. The second result generalizes the first result to random censorship model. The later also generalizes one dimensional central limit theorem of Stute(6) to a process version. These results may be used in the nonparametric statistical inference.

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Practical Numerical Model for Nonlinear Analyses of Wave Propagation and Soil-Structure Interaction in Infinite Poroelastic Media (무한 다공성 매질에서의 비선형 파전파 해석과 지반-구조물 상호작용 해석을 위한 실용적 수치 모형)

  • Lee, Jin Ho
    • Journal of the Earthquake Engineering Society of Korea
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    • v.22 no.7
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    • pp.379-390
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    • 2018
  • In this study, a numerical approach based on mid-point integrated finite elements and a viscous boundary is proposed for time-domain wave-propagation analyses in infinite poroelastic media. The proposed approach is accurate, efficient, and easy to implement in time-domain analyses. In the approach, an infinite domain is truncated at some distance. The truncated domain is represented by mid-point integrated finite elements with real element-lengths and a viscous boundary is attached to the end of the domain. Given that the dynamic behaviors of the proposed model can be expressed in terms of mass, damping, and stiffness matrices only, it can be implemented easily in the displacement-based finite-element formulation. No convolutional operations are required for time-domain calculations because the coefficient matrices are constant. The proposed numerical approach is applied to typical wave-propagation and soil-structure interaction problems. The model is verified to produce accurate and stable results. It is demonstrated that the numerical approach can be applied successfully to nonlinear soil-structure interaction problems.